<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<form>
			<div>
				output:代表输出结果
			1 + 1 = <output>2</output>
			</div>
			
			<!-- h4的下拉菜单 -->
			<select>
				<option value ="">1</option>
				<option value ="">2</option>
				<option value ="">3</option>
			</select>
			
			<!-- h5新增datalist实现下拉菜单 
			    1、datalist需要搭配input标签一起实现
				2、（input添加list + datalist添加id  保持一致）
				3、必须设置value的值
			-->
			<input type="text" list="a">
			<datalist id="a">
				<option value ="1">1</option>
				<option value ="2">2</option>
				<option value ="3">3</option>
			</datalist>
		</form>
	</body>
</html>
